Electric feeler



march mm:

Aug. 4, 1942. c. DARWIN ELECTRIC FEEL-ER Filed July 5, 1941 luvs NT 0 R CLIFFORD DARWIN AT TORNEY Patented Aug. 4, 1942 Search Room ELECTRIC FEELER Clifford Darwin, Worcester, Mass., assignor to Crompton & Knowles Loom Works, Worcester, Mass, a corporation of Massachusetts Application July 5, 1941, Serial No. 401,236

9 Claims. (Cl. 139273) This invention relates to electric weft detectors for looms and it is the general object of the invention to provide a durable detector which will exert very light pressure on the weft at the time of operation.

When weft detectors are used in connection with very fine yarns it is desirable to reduce the pressure of contact between the detector tips and the yarn to a minimum to avoid yarn abrasion or breakage. It is an important object of my present invention to provide small detector tips held yieldingly in detecting position by weak springs mounted in a yieldable carrier. The carrier is held in rear position by stronger springs than those which maintain the detector tips in normal position, hence the tips will move forwardly until the yarn strikes the rear part of the carrier, after which the latter will also move forwardly but will have a larger area of contact with the weft than do the tips. The weft is therefore subjected to low pressure through out the detecting operation.

It has been customary heretofore to provide electric weft detectors with sliding detector tips having contact with guides or the like on a base and connected to the loom controlling circuit. In such detectors there is little or no lateral pressure exerted on the detector wires tending to hold them in close contact with the surfaces along which they slide and there is consequently a variation in the amount of resistance which the sliding contact offers to the flow of current through the external circuit. It is a further object of my present invention to provide the slidable tips previously mentioned with flexible electric current conducting cables which are connected to the external circuit. With such a construction there is little or no variation in the resistance to the flow of current within the detector.

It is a further object of my present invention to hold the detector tips yieldingly in rear position by means of light coiled compression springs through which the flexible conductors extend. The springs serve not only to hold the carrier in normal detecting position but also act as shields or guards to protect the flexible cables and hold them away from adjacent parts which they might otherwise engage when tips slide on the carrier.

It is a more specific object of my present invention to provide both the carrier and the base on which it slides with coiled springs through which extend flexible electric current conducting cables, each tip of the carrier being associated with a light spring and a contact which engages a second contact held in position by a stronger spring in the base. The latter spring acts as a shield for the flexible cable which is connected to the external loom controlling circuit. In a modified form of the invention I use a single flexible cable which extends through a single contact stud or the like against which both springs act.

With these and other objects in view which will appear as the description proceeds, my invention resides in the combination and arrangement of parts hereinafter described and set forth.

In the accompanying drawing, wherein a convenient embodiment of my invention is set forth,

Fig. 1 is a plan of the preferred form of weft detector showing it at the instant of contact between the bobbin and detector tips,

Fig. 2 is a View similar to a portion of Fig. l, but showing the carrier moved forwardly during a detecting operation,

Fig. 3 is a vertical section on line 3-3 of Fig. 1,

Fig. 4 is an enlarged vertical section on line 44 of Fig. 1,

Figs. 5 and 6 are sections on lines 55 and 6-6, respectively, of Fig. 1, and

Fig. '7 is a view similar to part of Fig. 4 but showing a modified form of the invention.

In Fig. 1 I have shown a lay L carrying a shuttle S in which is located a bobbin B wound with a mass of weft W. The barrel of the bobbin is provided with a metallic ferrule l0 which is ordinarily covered by the weft but becomes exposed as weft exhaustion approaches. The lay moves forwardly to present the bobbin to a weft detector designated generally at D and the latter will ordinarily have contact with the bobbin on alternate beats of the loom, although this timing with respect to the cycle of the loom is not essential. A support ll held to the loom frame not shown supports the weft detector D.

In carrying my present invention into effect, I provide a casing C formed of insulating material having a body I2 through which extend bolts l3 to fasten the detector to the support II. The detector body is provided with a pair of spaced electrically insulated contact plates l5 and I6 held fixed with respect to the detector by means of screws I1 and I8, respectively. Wires I9 and 20 lead, respectively, from the plates I5 and IE to an external loom controlling circuit not shown. This circuit may be of any approved form and will ordinarily include an electro-magnetic device such as the solenoid not set forth herein, which upon actuation will effect a change in loom operation, such for instance as weft replenishment.

The body l2 has extending rearwardly therefrom a flattened arm 25 having formed therein a rearwardly extendingslot 26. A cover 21 secured to the arm 25 as at 28 closes the upper part of the slot 26. Slidably mounted in the slot is a carrier 30 made of electric insulating material and having a central longitudinal slot 3| through which extends a guide and stop pin 32 held to the arm 25 and extending through the cover 21.

The base of the detector is provided with two spaced substantially parallel bores 35 which communicate at their rear ends with the slot 26. Each bore has mounted therein a relatively strong compression coil spring 36 the rear coils of which in the preferred form extend over and may be secured to the front reduced end 31 of a contact head 38 slidable forwardly in the bore which contains it. The front end of each spring 36 is in engagement with the corresponding contact plate, the latter serving as a stop to confine the spring within its bore. The head 38 has a compact surface 39 which extends rearwardly as shown for instance in Fig. 4.

The slide carrier 30 is provided with a pair of comparatively small bores 45 into the forward end of each of which is driven the reduced end 46 of a contact head 41 similar to head 38 and having a contact surface 48 for engagement with the contact surface 39 of the associated head 33. The rear end of each bore 45 normally engages the shoulder 50 of a small detector contact tip which projects slightly beyond the rear surface 52 of the carrier 30 for engagement with the surface to be detected. The head 58 is slidable forwardly in the bore 45 and is held normally and yieldingly in rear position by a comparatively light compression spring 55 which is located between the reduced end 46 of head 41 and the shoulder 50. The reduced end 46 has a driving fit with the front end of the bore which receives it and the spring 55 is too weak to dis lodge the head 41 from the carrier. The heads 38 and 41, and also the tip 5| and its shoulder 58 are made of electric current conducting material.

Each shoulder 50 receives as at 68 the rearward end of a flexible multi-strand electric current conducting cable 8| which extends through the corresponding spring 55 and into the corresponding reduced end 46, as at 62. The cable may be soldered or otherwise secured to the parts 46 and 50 to conduct current between them. The head 38 has extending thereinto as at 65 a second fiexible multi-strand electric current conducting cable 56 located within the spring 36. The front end of each cable 66 extends through a hole 61 in the corresponding contact plate to be held under the associated screw.

Under normal conditions the springs 36 hold the carrier 39 in rear position against a stop pin 32. and these springs also maintain contact between the surfaces 39 and 48. The springs 55 which are weaker than the springs 36 hold the detector tips 5| normally in the rearward extended position shown in Fig. 1. As the lay advances the surface to be detected first engages the tips 5| and moves them forwardly relatively to the carrier 36 to the position shown in Fig. 2 against the action of light springs 55. During this forward motion of the tips the flexible cables 6| bend on themselves. As the lay continues to advance the surface to be detected engages the rear surface 52 of the carrier 38, after which the latter moves forwardly against the action of the heavier springs 36 within the detector base. The force which compresses the springs 36 is derived from the lay and is communicated through the contacting surfaces 39 and 48. As the carrier slides forwardly the cables 66 bend on them-- selves within springs 36.

So long as suificient weft for continued weaving is present the tips 5| will be insulated from each other, but as weft exhaustion approaches the ferrule I0 is uncovered and connects the tips 5| electrically. The springs hold the tips against the ferrule throughout the detecting operation even though other parts of the ferrule strike the surface 52 of carrier 38 to move the latter forwardly. When the ferrule strikes a tip it is electrically connected to the corresponding wire of the external circuit by means of cable 6|, head 41, surfaces 48 and 39, head 38, cable 66, and the associated contact plate. Thus it will be seen that the ferrule is electrically connected to the loom controlling circuit by a train of connections which involves no sliding electrical contact. The feeler tips and the carrier 38 are slidable with respect to the detector base however and the flexible cables 6| and 66 bend on themselves to accommodate the forward motion of the tips and carrier. The springs 36 and 55 may assist in conducting current but are not relied upon for this purpose. The flexible conductors take the greater part of the current and thus protect the springs against loss of temper through heating incident to the flow of current.

In the preferred form of the invention already described the circuit from the feeler tip to the contact plate is made through the abutting surfaces 39 and 48. In the modified form of my invention I replace the two heads 38 and 41 with a single bushing shown more particularly in Fig. 7 where all parts of the detector are similar to corresponding parts of the preferred form except the bushing and the cable. In Fig. 7 the feeler tip 10 is secured to the rear end of a flexible cable 1| which extends through a bushing 12 having a sleeve 13 driven into the carrier and a shoulder 14 to engage the forward edge of the carrier. The bushing 12 also has a second shoulder 15 which receives the rearward thrust of the large spring 36 the rear coils of which surround a sleeve 16 projecting forwardly from the bushing. Each cable 1| extends entirely through the bushing and its forward end is connected as in the preferred form. By this modified construction I eliminate the contact within the detector provided by the surfaces 39 and 48 in the preferred form. If desired the modified form may be altered to provide the rear part of cable 1| with fewer strands than the front part in view of the fact that the diameter of spring 55 is less than the diameter of spring 36. The modified form of the invention operates in a manner similar to the preferred form and like the latter, has no sliding electrical contact. The cable 1| may, if desired, be made in two parts each connected to the bushing and one extending rearwardly to the tip while the other extends forwardly.

From the foregoing it will be seen that I have provided a simple form of electric weft detector wherein the detector tips move forwardly on the carrier under light spring resistance, after which the carrier slides on the base, and that electric current is conducted from the tips to the loom controlling circuit without passing through a sliding electric contact. This result is possible Search Room by the employment of the flexible cables. It

will also be seen that the springs 38 and 55 serve not only to maintain the carrier and tips, respectively, in yielding rearward position, but also act as guards for the flexible conductors which lie within them. The tips 5| yield under very light pressure against the action of springs 55, while the heavier springs 36 are compressed by a force which is transmitted from the bobbin through the carrier 30. The yarn being detected is therefore exposed to very low contact pressures throughout the detecting operation.

Having thus described my invention it will be seen that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but what I claim is:

1. In an electric weft detector for a loom, a carrier formed of electric insulating material, a detector tip projecting beyond the rear end of the carrier and having a portion extending into and slidable with respect to the carrier, an electric contact fixed to the forward end of the carrier, a coiled compression spring within the carrier to engage that part of the tip which extends within the carrier and hold said tip yieldingly in rear detecting position, and a flexible electric conductor electrically connecting the tip and the contact and located principally within the coiled spring.

2. In an electrical weft detector provided with a base having an electrode for connection with a loom controlling circuit, a carrier formed of electrical insulating material supported by the base. a detector tip slidably mounted in the rear part of the carrier, a contact mounted at the front end of the carrier, means to connect the contact electrically to the electrode, a coiled spring within the carrier to hold the tip yieldingly in rearward detecting position, and a flexible electrical conductor electrically connecting the tip and contact and located principally within the coiled spring.

3. In an electric weft detector for a loom, a carrier formed of electric insulating material, a detector tip slidably mounted on and projecting beyond the rear end of the carrier, a contact fixed with respect to the forward end of the carrier, a coiled compression spring within the carrier extending between the contact and the tip and tending normally to hold the latter yieldingly in rearward detecting position, and a flexible electric conductor electrically connecting the tip and the contact and extending longitudinally within the coiled spring.

4. In an electrical weft detector havinga base, a carrier slidable backwardly and forwardly on the base, a detector tip slidably mounted on and projecting beyond the rear end of the carrier, an electrode at the forward end of the base, relatively weak coiled spring means supported by the carrier tending to hold the tip yieldingly in rearward position, stronger coiled spring means supported by the base and tending to hold the carrier yieldingly in rearward position with respect to the base, and flexible electric conductor means located principally ithin the spring means and electrically connecting the tip with the contact electrode.

5. In an electric Weft detector having a base, a carrier projecting rearwardly from and slidable on the base, relatively strong compression coil spring means to hold the carrier yieldingly in rearward position with respect to the base, a

contact electrode on the forward end of the base, a detector tip slidably mounted on and project ing rearwardly from the rear end of the carrier, relatively weak compression spring means supported by the carrier and tending to hold the tip yieldingly in rearward detecting position with respect to the carrier, a contact on the forward end of the carrier, a contact on the rear end of the strong spring means held by the latter in engagement with the contact on the forward end of the carrier, and flexible electric current conducting means electrically connecting the tip and the contact on the forward end of the carrier, and other flexible electric current conductor means electrically connecting the first named contact electrode with the contact on the rear end of the strong spring means, said flexible conducting means located principally within the coiled spring means.

6. In an electric weft detector having a base, a carrier projecting rearwardly from and slidable on the base, relatively strong compression coiled spring means within the base to hold the carrier yieldingly in rearward position with respect to the base, an electrode on the forward end of the base. a detector tip slidably mounted on and projecting rearwardly beyond the rear end of the carrier. a relatively weak compression spring within the carrier engaging and tending to hold the tip yieldingly in rearwardly detecting position with respect to the carrier, a contact fixed with respect to the carrier and having the rearwardly directed force of the strong spring means directed thereagainst to hold the carrier yieldingly in rearward position with respect to the base, the rear end of said contact engaging the forward end of the relatively weak spring means and cooperating with the latter to hold the tip yieldingly in rear detecting position, and flexible electric current conducting cable means located principally within said spring means and electrically connecting the tip, the contact and the electrode.

7. In an electrical weft detector having a base, a carrier slidable backwardly and forwardly on the base, a detector tip slidably mounted on and projecting beyond the rear end of the carrier, an electrode at the forward end of the base, relatively weak coiled spring means supported by the carrier tending to hold the tip yieldingly in rearward position, a stud on the carrie engaging the forward end of the weak spring means and cooperating therewith to hold the tip in rear position relatively to the carrier, stronger coiled spring means supported by the base engaging the stud to hold the carrier in rear position relatively to the base, and flexible conductor means located principally within the spring means and connecting electrically the tip and electrode.

8. In an electrical weft detector having a base, a carrier slidable backwardly and forwardly on the base, a detector tip slidably mounted on and projecting beyond the rear end of the carrier. an electrode at the forward end of the base, relatively weak coiled spring means supported by the carrier tending to hold the tip yieldingly in rearward position, a stud on the carrier engaging the forward end of the weak spring means and cooperating therewith to hold the tip in rear position relatively to the carrier, stronger coiled spring means supported by the base engaging the stud to hold the carrier in rear position relatively to the base, and flexible conductor means located principally within the spring means and extending through the stud and electrically connecting the tip and electrode.

9. In an electrical weft detector having a base, a carrier slidable backwardly and forwardly on the base, a detector tip slidably mounted on and projecting beyond the rear end of the carrier, an electrode at the forward end of the base, relatively weak coiled spring means supported by the carrier tending to hold the tip yieldingly in rearward position, a stud on the carrier engagl0 ing the forward end of the weak spring means and cooperating therewith to hold the tip in rear position relatively to the carrier, stronger coiled spring means supported by the base engaging the stud to hold the carrier in rear position relatively to the base, and flexible conductor means located principally within the spring means and electrically connecting the tip, stud and electrode.

CLIFFORD DARWIN. 

